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50L6GT

Glass-octal beam-power tube widely used in audio-output stages of AC/DC radio receivers, delivering substantial power from low supply voltages.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7AC
Socket code: IO
Base pins: 8
Nominal heater: 50 V / 150 mA

Description

Glass-octal beam power tube used in the audio output stage of AC/DC radio receivers. Extracted from the supplied RCA Receiving Tube Manual excerpt.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7AC
Socket code: IO
Base pins: 8
Nominal heater voltage: 50 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7AC - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1Pin 1	—	NC	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN2Pin 2	—	H — Heater	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN3Pin 3	A	P — Plate (Anode)	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN4Pin 4	A	G2 — Screen Grid	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN5Pin 5	A	G1 — Control Grid	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN7Pin 7	—	H — Heater	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN8Pin 8	A	BP — Beam-Forming PlateGroup AC8	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN8Pin 8	A	K — CathodeGroup AC8	Verified 12L6GT/25L6GT manufacturer basing, 7AC

Section ratings

1 physical section, each with unique specifications.

Section 1

Beam Power

X-ray radiationInterelectrode capacitances

Plate resistance: 28000 Ω
Transconductance: 0.008 S
Amplification factor: 83
Max plate voltage: 200 V
Max screen voltage: 125 V
Max plate dissipation: 10 W
Max screen dissipation: 1.25 W
Max cathode current: 55 mA

200-V plate operating column used for promoted characteristics.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1939 Arcturus

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Plate voltage
110 V
Screen-grid voltage
110 V
Control-grid voltage
-7.5 V
Plate current
45 mA
Load resistance
2000 ohm
Power output
1.5 W
Total harmonic distortion
10 %

Data set 02

1948 Brimar Radio Valve Manual

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Plate Voltage
110 V
Plate Current
49 mA
Screen Voltage
110 V
Screen Current
4 mA
Control Grid Voltage
-7.5 V
Optimum Load
1500 ohm
Power Output
2.1 W

Characteristic

Plate Resistance
10000 ohm
Transconductance
9000 µS

Data set 03

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Characteristics

Anode Voltage
200 V
Anode Current
50 mA
Screen Voltage
110 V
Control Grid Voltage
-8 V
Optimum Load
3000 ohm

Other

Power Output
4.3 W
ClassA

Data set 04

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Maximum plate voltage
200 V
Published handbook rating
Maximum screen voltage
125 V
Published handbook rating
Plate voltage
200 V
ClassA
Screen voltage
125 V
ClassA
Control-grid bias
46 V
ClassA
Plate current
28 mA
ClassA
Screen current
2.2 mA
ClassA
Load resistance
4000 ohm
ClassA
Power output
3.8 W
ClassA

Characteristic

Plate resistance
28000 ohm
Published handbook characteristic
Transconductance
8000 µS
Published handbook characteristic
Heater/filament voltage
50 V
Published heater/filament rating
Heater/filament current
150 mA
Published heater/filament rating

Data set 05

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Characteristic

HeaterOrFilamentVoltage
50 V
HeaterOrFilamentCurrent
150 mA

Other

Power Output
4.3 W
ClassA

Data set 06

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater voltage
50 V
Heater current
150 mA
Plate voltage
110 V
ClassA1
Screen voltage
110 V
ClassA1
Power output
2.1 W
ClassA1;110VPlate
Power output
3.8 W
ClassA1;200VPlate

Characteristic

Plate resistance
13000 ohm
110VPlate
Transconductance
8000 uS
110VPlate

Data set 07

1965 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Capacitance

Grid-to-plate capacitance
0.8 pF
Input capacitance
15 pF
Output capacitance
9 pF

Other

Plate voltage
200 V
ClassA

Characteristics

Transconductance
9500 uS
ClassA
Plate resistance
30000 Ohm
ClassA

Data set 08

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Plate voltage maximum
200 V
Screen voltage maximum
125 V
Class-A plate voltage low
110 V
ClassA
Class-A power output low
2.1 W
ClassA
Class-A plate voltage high
200 V
ClassA
Class-A power output high
4.3 W
ClassA

Characteristics

Class-A plate resistance low
13000 ohm
ClassA
Class-A plate resistance high
30000 ohm
ClassA

Application

Application
AC/DC receiver audio output

Data set 09

1966 Tung Sol Electronic Tubes 3 of 4

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Typical plate voltage
200 V
ClassA
Typical screen voltage
125 V
ClassA
Zero-signal plate current
49 mA
ClassA
Load resistance
4000 ohm
ClassA
Maximum-signal power output
3.8 W
ClassA
Maximum plate voltage
200 V
PromotedValue
Maximum screen voltage
125 V
PromotedValue
Maximum plate dissipation
10 W
PromotedValue
Maximum screen dissipation
1.25 W
PromotedValue
Maximum Grid #2 Voltage
125 V
PublishedTable
Maximum Grid #2 Dissipation
1.25 W
PublishedTable
Heater Current 0.15
15 A
PublishedTable

Characteristics

Plate resistance
24000 ohm
PromotedValue
Transconductance
0.005 A/V
PromotedValue
Max. 50 Volts
150 mA
PublishedTable

Data set 10

1971 RCA HB3 Binder 5 of 7

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater voltage
50 V
Heater current
150 mA
Plate voltage
200 V
ClassA
Screen voltage
110 V
ClassA
Grid voltage
-8 V
ClassA
Zero-signal plate current
50 mA
ClassA
Maximum-signal plate current
55 mA
ClassA
Load resistance
3000 ohm
ClassA
Power output
4.3 W
ClassA
Maximum plate voltage
200 V
Maximum screen voltage
117 V
Plate dissipation
10 W
Screen dissipation
1.25 W

Characteristic

Plate resistance
30000 ohm
ClassA
Transconductance
9500 uS
ClassA

Data set 11

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Capacitance

Grid-to-plate capacitance
0.6 pF
Input capacitance
15 pF
Output capacitance
9.5 pF

Other

Plate supply voltage
200 V
ClassA CathodeBias
Screen supply voltage
125 V
ClassA CathodeBias
Maximum-signal plate current
47 mA
ClassA CathodeBias
Maximum-signal screen current
8.5 mA
ClassA CathodeBias
Load resistance
4000 ohm
ClassA CathodeBias
Power output
3.8 W
ClassA CathodeBias